Properly handle reexport of foreign items.

Handles `pub use` of `extern { fn, static, type }`. Also plug in some more
`match` arms where handling `extern type` is reasonable.

Fixed #46098.

src/librustdoc/clean/mod.rs

@@ -2970,6 +2970,7 @@ fn register_def(cx: &DocContext, def: Def) -> DefId {
         Def::Struct(i) => (i, TypeKind::Struct),
         Def::Union(i) => (i, TypeKind::Union),
         Def::Mod(i) => (i, TypeKind::Module),
+        Def::TyForeign(i) => (i, TypeKind::Foreign),
         Def::Static(i, _) => (i, TypeKind::Static),
         Def::Variant(i) => (cx.tcx.parent_def_id(i).unwrap(), TypeKind::Enum),
         Def::SelfTy(Some(def_id), _) => (def_id, TypeKind::Trait),

src/librustdoc/visit_ast.rs

@@ -306,6 +306,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 Def::Struct(did) |
                 Def::Union(did) |
                 Def::Enum(did) |
+                Def::TyForeign(did) |
                 Def::TyAlias(did) if !self_is_hidden => {
                     self.cx.access_levels.borrow_mut().map.insert(did, AccessLevel::Public);
                 },
@@ -348,6 +349,17 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 self.inlining = prev;
                 true
             }
+            hir_map::NodeForeignItem(it) if !glob => {
+                // generate a fresh `extern {}` block if we want to inline a foreign item.
+                om.foreigns.push(hir::ForeignMod {
+                    abi: tcx.hir.get_foreign_abi(it.id),
+                    items: vec![hir::ForeignItem {
+                        name: renamed.unwrap_or(it.name),
+                        .. it.clone()
+                    }].into(),
+                });
+                true
+            }
             _ => false,
         };
         self.view_item_stack.remove(&def_node_id);

src/test/rustdoc/foreigntype-reexport.rs

@@ -0,0 +1,66 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(extern_types)]
+
+mod sub {
+    extern {
+        /// Another extern type.
+        pub type C2;
+        pub fn f2();
+        pub static K: usize;
+    }
+}
+
+pub mod sub2 {
+    extern {
+        // @has foreigntype_reexport/sub2/foreigntype.C.html
+        pub type C;
+        // @has foreigntype_reexport/sub2/fn.f.html
+        pub fn f();
+        // @has foreigntype_reexport/sub2/static.K3.html
+        pub static K3: usize;
+    }
+}
+
+mod sub3 {
+    extern {
+        pub type C4;
+        pub fn f4();
+        pub static K4: usize;
+        type X4;
+    }
+}
+
+// @has foreigntype_reexport/foreigntype.C2.html
+// @has foreigntype_reexport/fn.f2.html
+// @has foreigntype_reexport/static.K2.html
+// @has foreigntype_reexport/index.html '//a[@class="foreigntype"]' 'C2'
+// @has foreigntype_reexport/index.html '//a[@class="fn"]' 'f2'
+// @has foreigntype_reexport/index.html '//a[@class="static"]' 'K2'
+pub use self::sub::{C2, f2, K as K2};
+
+// @has foreigntype_reexport/index.html '//a[@class="foreigntype"]' 'C'
+// @has foreigntype_reexport/index.html '//a[@class="fn"]' 'f'
+// @has foreigntype_reexport/index.html '//a[@class="static"]' 'K3'
+// @has foreigntype_reexport/index.html '//code' 'pub use self::sub2::C as C3;'
+// @has foreigntype_reexport/index.html '//code' 'pub use self::sub2::f as f3;'
+// @has foreigntype_reexport/index.html '//code' 'pub use self::sub2::K3;'
+pub use self::sub2::{C as C3, f as f3, K3};
+
+// @has foreigntype_reexport/foreigntype.C4.html
+// @has foreigntype_reexport/fn.f4.html
+// @has foreigntype_reexport/static.K4.html
+// @!has foreigntype_reexport/foreigntype.X4.html
+// @has foreigntype_reexport/index.html '//a[@class="foreigntype"]' 'C4'
+// @has foreigntype_reexport/index.html '//a[@class="fn"]' 'f4'
+// @has foreigntype_reexport/index.html '//a[@class="static"]' 'K4'
+// @!has foreigntype_reexport/index.html '//a[@class="foreigntype"]' 'X4'
+pub use self::sub3::*;